Access to a computer system in its broad sense connotes the utilization of computing resources to create, modify, or destroy information bound or associated with the computing resources. Access must embrace the notion of graded access. That is, some individuals must be absolutely barred under all circumstances from utilizing resources while others may participate for limited periods of time, utilizing combinations of resources, and/or data sets. With the advent of remote access capabilities in systems such as "dial-up access" and the easy availability of small "personal" computers, systems have become increasingly susceptible to the whims of the proverbial "hacker" who often will use a remote access path to avoid being easily located. Such an individual, usually with the aid of his own local computer, will try to penetrate the access barriers of a target dial-up computing system. The hacker can try random and adaptive patterns employing logon identities and passwords. Some prior art systems require the user to supply a single "password". More complex methods require more information be supplied by a user than a single password. Here, the speed and repetitive ease with with different passwords may be tried out permits the computer-assisted hacker to guess and/or adaptively constrain the number of trials until a true access to the target system can be achieved.
In the computer art, all prior VM authorization mechanisms rely principally upon a password match. In the event of mismatch or a repeated pattern of mismatch, entry is merely denied. In other systems, such as IBM's Resource Access Control Facility (RACF) described in OS/VS2 MVS RACF Command Language Reference, IBM publication SC28-0733, other criteria such as location or a value of a system clock may be used to control access. Significantly, it is known in the telephone art to bind an accessing instrument to other than a target system when a dialed number is mappable only onto either a false busy or a redial answer-back request.
Cannavino et al, U.S. Pat. No. 4,430,705, "Authorization Mechanism for Establishing Addressability to Information in Another Address Space", issued Feb. 7, 1984, shows an authorization mechanism by which a process in one logical interface or partition may access information in another logical interface or partition. Also of interest is Yost, copending U.S. patent application Ser. No. 06/459,746, filed Jan. 21, 1983, now abandoned, entitled "Controlling Multiple Distributed Computations in a Multi CPU Environment from a Single Port". Yost teaches a method for reconfiguring logical views and binding dissimilar real configurations to the logical views.